Răspuns:
1. 0,5 *x = [tex]\frac{2*3+1}{3} * \frac{1*7+3}{7}[/tex]
[tex]\frac{5x}{10}[/tex] = [tex]\frac{7}{3} * \frac{10}{7}[/tex] [tex]\frac{5x}{10}[/tex] = [tex]\frac{10}{3}[/tex] => x= [tex]\frac{10}{3} *\frac{5}{10}[/tex] = [tex]\frac{5}{3}[/tex]
x= [tex]\frac{5}{3}[/tex]
2. 10/998 = 0.01002
3. a+b+c= 560
[tex]\frac{a}{2} = \frac{b}{11} =\frac{c}{7}[/tex]= k => a= 2k b= 11k c= 7k
2k+ 11k+7k= 560
20k = 560 k= 560/20= 28
a= 2*28= 56
b= 11*28= 308
c= 7*28= 196
4.
400- 36= 364 seminte incoltite
p%= 364*100/400= 91 %
5. 48 * [tex]\frac{15}{100}[/tex]= 48* [tex]\frac{3}{20}[/tex]= [tex]\frac{48*3}{5*4}[/tex]= [tex]\frac{12*3}{5} =\frac{36}{5}[/tex]
48- [tex]\frac{36}{5}[/tex]= [tex]\frac{48*5-36}{5} = \frac{240-36}{5}[/tex]= 204:5= 40, 8 lei pretul dupa reducere
6. 4*( 3x-y) = 5*(2x+y)
12x- 4y = 10 x + 5y
12x-10x= 5y+4y
2x= 9y => [tex]\frac{x}{y} =\frac{2}{9}[/tex]
